diff --git a/composer.json b/composer.json
index 59d04741..c3ed73ac 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,8 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "require": {
-        "php": "^7.1 || ^8.0",
+        "php": "^7.3 || ^8.0",
+        "silverstripe/framework": "^4.10@dev",
         "silverstripe/cms": "^4.7@dev",
         "silverstripe/admin": "^1.7@dev",
         "silverstripe/versioned": "^1.7@dev",
@@ -26,7 +27,7 @@
         "silverstripe/vendor-plugin": "^1"
     },
     "require-dev": {
-      "silverstripe/recipe-testing": "1.x-dev"
+      "silverstripe/recipe-testing": "^2"
     },
     "suggest": {
         "silverstripe/elemental-blocks": "Adds a set of common SilverStripe content block types",
diff --git a/docs/en/advanced_setup.md b/docs/en/advanced_setup.md
index eaf641c5..464f12da 100644
--- a/docs/en/advanced_setup.md
+++ b/docs/en/advanced_setup.md
@@ -300,7 +300,7 @@ TractorCow\Fluent\Model\Locale:
 In the case your fixture needs to contain data for only a single locale you can specify your desired locale in your unit test like this:
 
 ```php
-protected function setUp()
+protected function setUp(): void
 {
     // Set locale for fixture creation
     FluentState::singleton()->withState(function (FluentState $state) {
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 3e41eee8..0d087d59 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,8 +1,9 @@
 <phpunit bootstrap="vendor/silverstripe/framework/tests/bootstrap.php" colors="true">
-    <testsuite name="Default">
-        <directory>tests</directory>
-    </testsuite>
-
+    <testsuites>
+        <testsuite name="Default">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
     <filter>
         <whitelist addUncoveredFilesFromWhitelist="true">
             <directory suffix=".php">src/</directory>
diff --git a/tests/BaseElementTest.php b/tests/BaseElementTest.php
index d489509d..7d829c5a 100644
--- a/tests/BaseElementTest.php
+++ b/tests/BaseElementTest.php
@@ -107,7 +107,7 @@ public function testLink()
     {
         $element = $this->objFromFixture(ElementContent::class, 'content1');
 
-        $this->assertContains($element->getPage()->Link(), $element->Link());
+        $this->assertStringContainsString($element->getPage()->Link(), $element->Link());
     }
 
     public function testGetEditLink()
@@ -118,14 +118,14 @@ public function testGetEditLink()
         $element = $this->objFromFixture(ElementContent::class, 'content1');
         $editLink = $element->getEditLink();
 
-        $this->assertContains('http://example.com', $editLink, 'Link should be absolute');
-        $this->assertContains('pages/edit', $editLink, 'Link should contain reference to the page');
+        $this->assertStringContainsString('http://example.com', $editLink, 'Link should be absolute');
+        $this->assertStringContainsString('pages/edit', $editLink, 'Link should contain reference to the page');
     }
 
     public function testGetIcon()
     {
         $element = new ElementContent();
-        $this->assertContains('class="font-icon-block-content"', $element->getIcon());
+        $this->assertStringContainsString('class="font-icon-block-content"', $element->getIcon());
 
         Config::modify()->set(ElementContent::class, 'icon', '');
         $this->assertEmpty($element->getIcon());
diff --git a/tests/Behat/Context/FeatureContext.php b/tests/Behat/Context/FeatureContext.php
index 9fc1995b..7c65ae36 100644
--- a/tests/Behat/Context/FeatureContext.php
+++ b/tests/Behat/Context/FeatureContext.php
@@ -3,6 +3,7 @@
 
 use Behat\Behat\Hook\Scope\BeforeScenarioScope;
 use Behat\Mink\Element\NodeElement;
+use PHPUnit\Framework\Assert;
 use SilverStripe\BehatExtension\Context\BasicContext;
 use SilverStripe\BehatExtension\Context\SilverStripeContext;
 use SilverStripe\Framework\Tests\Behaviour\CmsFormsContext;
@@ -43,10 +44,10 @@ public function iShouldSeeTheEditFormForBlock($negative, $position)
         $form = $block->find('css', '.element-editor-editform');
 
         if ($iShouldNotSee) {
-            assertTrue(!$form || !$form->isVisible(), 'I see the form! Try again later.');
+            Assert::assertTrue(!$form || !$form->isVisible(), 'I see the form! Try again later.');
         } else {
-            assertNotNull($form, 'Edit form not found');
-            assertTrue($form->isVisible());
+            Assert::assertNotNull($form, 'Edit form not found');
+            Assert::assertTrue($form->isVisible());
         }
     }
 
@@ -55,7 +56,7 @@ public function iShouldSeeTheEditFormForBlock($negative, $position)
      */
     public function iShouldSeeAListOfBlocks()
     {
-        assertNotEmpty($this->getBlocks());
+        Assert::assertNotEmpty($this->getBlocks());
     }
 
     /**
@@ -63,7 +64,7 @@ public function iShouldSeeAListOfBlocks()
      */
     public function iShouldSeeAnEmptyListOfBlocks()
     {
-        assertEmpty($this->getBlocks());
+        Assert::assertEmpty($this->getBlocks());
     }
 
     /**
@@ -71,7 +72,7 @@ public function iShouldSeeAnEmptyListOfBlocks()
      */
     public function iShouldSeeBlock($position)
     {
-        assertNotNull($this->getSpecificBlock($position));
+        Assert::assertNotNull($this->getSpecificBlock($position));
     }
 
     /**
@@ -80,7 +81,7 @@ public function iShouldSeeBlock($position)
     public function iClickOnBlock($position)
     {
         $block = $this->getSpecificBlock($position);
-        assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
+        Assert::assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
         $block->click();
     }
 
@@ -91,7 +92,7 @@ public function iClickOnTheCaretButtonForBlock($position)
     {
         $block = $this->getSpecificBlock($position);
         $button = $this->getCaretButton($block);
-        assertNotNull($button, 'Caret button for block ' . $position . ' was not found in the page.');
+        Assert::assertNotNull($button, 'Caret button for block ' . $position . ' was not found in the page.');
         $button->click();
     }
 
@@ -102,7 +103,7 @@ public function iShouldSeeAsTheTitleForBlock($text, $position)
     {
         $block = $this->getSpecificBlock($position);
         $title = $block->find('css', '.element-editor-header__title');
-        assertEquals($title->getText(), $text);
+        Assert::assertEquals($title->getText(), $text);
     }
 
     /**
@@ -112,7 +113,7 @@ public function iShouldSeeAsTheSummaryForBlock($text, $position)
     {
         $block = $this->getSpecificBlock($position);
         $summary = $block->find('css', '.element-editor-summary__content');
-        assertEquals($summary->getText(), $text);
+        Assert::assertEquals($summary->getText(), $text);
     }
 
     /**
@@ -139,9 +140,9 @@ public function iShouldSeeThePublishButtonForBlock($negative, $position)
         $publishButton = $this->findPublishButton($position);
 
         if ($iShouldNotSee) {
-            assertNull($publishButton, 'Publish button displayed (but shouldn\'t)');
+            Assert::assertNull($publishButton, 'Publish button displayed (but shouldn\'t)');
         } else {
-            assertNotNull($publishButton, 'Publish button not displayed (but should be)');
+            Assert::assertNotNull($publishButton, 'Publish button not displayed (but should be)');
         }
     }
 
@@ -158,9 +159,9 @@ public function iShouldSeeTheUnpublishButtonForBlock($negative, $position)
         $unpublishButton = $this->findUnpublishButton($position);
 
         if ($iShouldNotSee) {
-            assertNull($unpublishButton, 'Unpublish button displayed (but shouldn\'t)');
+            Assert::assertNull($unpublishButton, 'Unpublish button displayed (but shouldn\'t)');
         } else {
-            assertNotNull($unpublishButton, 'Unpublish button not displayed (but should be)');
+            Assert::assertNotNull($unpublishButton, 'Unpublish button not displayed (but should be)');
         }
     }
 
@@ -172,7 +173,7 @@ public function iShouldSeeTheUnpublishButtonForBlock($negative, $position)
     public function iHoverOverBlock($position)
     {
         $block = $this->getSpecificBlock($position);
-        assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
+        Assert::assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
         $block->mouseOver();
     }
 
@@ -184,7 +185,7 @@ public function iHoverOverBlock($position)
     public function iHoverOverTheIconOfBlock($position)
     {
         $block = $this->getSpecificBlock($position);
-        assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
+        Assert::assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
         $icon = $block->find(
             'css',
             '.element-editor-header .element-editor-header__info .element-editor-header__icon-container'
@@ -204,7 +205,7 @@ public function stepIPressTheButtonInTheAddBlockPopover($text)
 
         // Selector preferable not font-icon, but other class shared among all buttons
         $button = $popover->find('css', '.font-icon-block-'. $blockType);
-        assertNotNull($button, "{$text} button not found in Add Block popover");
+        Assert::assertNotNull($button, "{$text} button not found in Add Block popover");
         $button->click();
     }
 
@@ -223,7 +224,7 @@ public function stepIPressTheButtonInTheActionMenuForBlock($buttonName, $blockNu
 
         $button = $popover->find('xpath', sprintf('/button[contains(text(), \'%s\')]', $buttonName));
 
-        assertNotNull($button, sprintf('Could not find button labelled "%s"', $buttonName));
+        Assert::assertNotNull($button, sprintf('Could not find button labelled "%s"', $buttonName));
 
         $button->click();
     }
@@ -274,10 +275,10 @@ public function theFieldForBlockShouldContain($field, $blockNumber, $negate, $co
     public function iClickOnTheReport($reportName)
     {
         $reportsTable = $this->getSession()->getPage()->find('css', '.all-reports-gridfield .grid-field__table');
-        assertNotNull($reportsTable, 'Report table could not be found');
+        Assert::assertNotNull($reportsTable, 'Report table could not be found');
 
         $report = $reportsTable->find('xpath', sprintf('//a[contains(text(), \'%s\')]', $reportName));
-        assertNotNull($report, 'Specified report "' . $reportName . '" could not be found.');
+        Assert::assertNotNull($report, 'Specified report "' . $reportName . '" could not be found.');
 
         $report->click();
 
@@ -327,10 +328,10 @@ protected function getSpecificBlock($position)
     protected function getArchiveButton($position)
     {
         $block = $this->getSpecificBlock($position);
-        assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
+        Assert::assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
 
         $button = $block->find('css', '.element-editor__actions-archive');
-        assertNotNull($button, 'Archive button not found');
+        Assert::assertNotNull($button, 'Archive button not found');
 
         return $button;
     }
@@ -344,7 +345,7 @@ protected function getArchiveButton($position)
     protected function findPublishButton($position)
     {
         $block = $this->getSpecificBlock($position);
-        assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
+        Assert::assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
 
         $button = $block->find('css', '.element-editor__actions-publish');
 
@@ -360,7 +361,7 @@ protected function findPublishButton($position)
     protected function findUnpublishButton($position)
     {
         $block = $this->getSpecificBlock($position);
-        assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
+        Assert::assertNotNull($block, 'Block ' . $position . ' was not found in the page.');
 
         $button = $block->find('css', '.element-editor__actions-unpublish');
 
@@ -376,7 +377,7 @@ protected function findUnpublishButton($position)
     protected function getCaretButton($block)
     {
         $button = $block->find('css', '.element-editor-header__expand');
-        assertNotNull($button, 'Caret button not found');
+        Assert::assertNotNull($button, 'Caret button not found');
 
         return $button;
     }
@@ -390,8 +391,8 @@ protected function findFieldInBlock($block, $name)
     {
         $label = $block->findAll('xpath', sprintf('//label[contains(text(), \'%s\')]', $name));
 
-        assertNotCount(0, $label, sprintf('Could not find a label for a field with the content "%s"', $name));
-        assertCount(
+        Assert::assertNotCount(0, $label, sprintf('Could not find a label for a field with the content "%s"', $name));
+        Assert::assertCount(
             1,
             $label,
             sprintf(
@@ -405,7 +406,7 @@ protected function findFieldInBlock($block, $name)
         $fieldId = $label->getAttribute('for');
         $field = $block->find('css', '#' . $fieldId);
 
-        assertNotNull($field, sprintf(
+        Assert::assertNotNull($field, sprintf(
             'Label found matching "%s" but there was no field that has the ID matching the "for" attribute ("#%s")',
             $name,
             $fieldId
diff --git a/tests/ElementControllerTest.php b/tests/ElementControllerTest.php
index d26fc867..2ef2b0e8 100644
--- a/tests/ElementControllerTest.php
+++ b/tests/ElementControllerTest.php
@@ -26,7 +26,7 @@ class ElementControllerTest extends FunctionalTest
         TestElement::class
     ];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         Versioned::set_stage(Versioned::DRAFT);
 
@@ -40,6 +40,6 @@ public function testForTemplate()
         $this->logInWithPermission('ADMIN');
         $controller = new TestElementController($element);
 
-        $this->assertContains('Hello Test', $controller->forTemplate());
+        $this->assertStringContainsString('Hello Test', $controller->forTemplate());
     }
 }
diff --git a/tests/ElementalAreaTest.php b/tests/ElementalAreaTest.php
index 91edd828..f5949cce 100644
--- a/tests/ElementalAreaTest.php
+++ b/tests/ElementalAreaTest.php
@@ -85,8 +85,8 @@ public function testForTemplate()
     {
         $area = $this->objFromFixture(ElementalArea::class, 'area1');
 
-        $this->assertContains('Hello Test', $area->forTemplate());
-        $this->assertContains('Hello Test 2', $area->forTemplate());
+        $this->assertStringContainsString('Hello Test', $area->forTemplate());
+        $this->assertStringContainsString('Hello Test 2', $area->forTemplate());
     }
 
     public function testCanBePublished()
diff --git a/tests/ElementalPageExtensionTest.php b/tests/ElementalPageExtensionTest.php
index b046bcb0..7ea2205e 100644
--- a/tests/ElementalPageExtensionTest.php
+++ b/tests/ElementalPageExtensionTest.php
@@ -26,7 +26,7 @@ class ElementalPageExtensionTest extends FunctionalTest
         TestPage::class,
     ];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
diff --git a/tests/Extensions/ElementalAreasExtensionTest.php b/tests/Extensions/ElementalAreasExtensionTest.php
index 97752fc7..ab47825d 100644
--- a/tests/Extensions/ElementalAreasExtensionTest.php
+++ b/tests/Extensions/ElementalAreasExtensionTest.php
@@ -25,7 +25,7 @@ class ElementalAreasExtensionTest extends SapphireTest
         TestUnusedElement::class,
     ];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
diff --git a/tests/Forms/ElementalAreaFieldTest.php b/tests/Forms/ElementalAreaFieldTest.php
index b2b20195..58141a6e 100644
--- a/tests/Forms/ElementalAreaFieldTest.php
+++ b/tests/Forms/ElementalAreaFieldTest.php
@@ -23,7 +23,7 @@ class ElementalAreaFieldTest extends SapphireTest
      */
     protected $field;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
diff --git a/tests/Forms/TextCheckboxGroupFieldTest.php b/tests/Forms/TextCheckboxGroupFieldTest.php
index fa7d6d5c..820f1395 100644
--- a/tests/Forms/TextCheckboxGroupFieldTest.php
+++ b/tests/Forms/TextCheckboxGroupFieldTest.php
@@ -15,7 +15,7 @@ class TextCheckboxGroupFieldTest extends SapphireTest
      */
     protected $field;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
diff --git a/tests/GraphQL/AddElementToAreaMutationTest.php b/tests/GraphQL/AddElementToAreaMutationTest.php
index c4eda5e6..5504074d 100644
--- a/tests/GraphQL/AddElementToAreaMutationTest.php
+++ b/tests/GraphQL/AddElementToAreaMutationTest.php
@@ -18,7 +18,7 @@ class AddElementToAreaMutationTest extends SapphireTest
         TestElement::class,
     ];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
         if (!class_exists(Schema::class)) {
@@ -50,20 +50,16 @@ public function testAddingBlocksInOrder()
         $this->assertIdsInOrder([$five, $one, $three, $two, $four], 'The fifth element is added first, after ID 0');
     }
 
-    /**
-     * @expectedException InvalidArgumentException
-     */
     public function testBadElementalArea()
     {
+        $this->expectException(InvalidArgumentException::class);
         $areaID = $this->objFromFixture(ElementalArea::class, 'one')->ID;
         $this->runMutation(TestElement::class, $areaID + 1);
     }
 
-    /**
-     * @expectedException InvalidArgumentException
-     */
     public function testOrderingByWrongElementalArea()
     {
+        $this->expectException(InvalidArgumentException::class);
         $firstArea = ElementalArea::get()->first();
         $elementInFirstArea = TestElement::create();
         $firstArea->Elements()->add($elementInFirstArea);
diff --git a/tests/GraphQL/DuplicateElementMutationTest.php b/tests/GraphQL/DuplicateElementMutationTest.php
index 3a61a487..38368e7f 100644
--- a/tests/GraphQL/DuplicateElementMutationTest.php
+++ b/tests/GraphQL/DuplicateElementMutationTest.php
@@ -12,7 +12,7 @@
 
 class DuplicateElementMutationTest extends SapphireTest
 {
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
         if (!class_exists(Schema::class)) {
diff --git a/tests/GraphQL/Legacy/AddElementToAreaMutationTest.php b/tests/GraphQL/Legacy/AddElementToAreaMutationTest.php
index 8755f520..fe83dbb6 100644
--- a/tests/GraphQL/Legacy/AddElementToAreaMutationTest.php
+++ b/tests/GraphQL/Legacy/AddElementToAreaMutationTest.php
@@ -19,7 +19,7 @@ class AddElementToAreaMutationTest extends SapphireTest
         TestElement::class,
     ];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
         if (class_exists(Schema::class)) {
@@ -51,20 +51,16 @@ public function testAddingBlocksInOrder()
         $this->assertIdsInOrder([$five, $one, $three, $two, $four], 'The fifth element is added first, after ID 0');
     }
 
-    /**
-     * @expectedException InvalidArgumentException
-     */
     public function testBadElementalArea()
     {
+        $this->expectException(InvalidArgumentException::class);
         $areaID = $this->objFromFixture(ElementalArea::class, 'one')->ID;
         $this->runMutation(TestElement::class, $areaID + 1);
     }
 
-    /**
-     * @expectedException InvalidArgumentException
-     */
     public function testOrderingByWrongElementalArea()
     {
+        $this->expectException(InvalidArgumentException::class);
         $firstArea = ElementalArea::get()->first();
         $elementInFirstArea = TestElement::create();
         $firstArea->Elements()->add($elementInFirstArea);
diff --git a/tests/GraphQL/Legacy/SortBlockMutationCreatorTest.php b/tests/GraphQL/Legacy/SortBlockMutationCreatorTest.php
index 4ea6c37b..fb8a7b03 100644
--- a/tests/GraphQL/Legacy/SortBlockMutationCreatorTest.php
+++ b/tests/GraphQL/Legacy/SortBlockMutationCreatorTest.php
@@ -17,7 +17,7 @@ class SortBlockMutationCreatorTest extends SapphireTest
         TestElement::class,
     ];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
         if (class_exists(Schema::class)) {
diff --git a/tests/GraphQL/SortBlockMutationCreatorTest.php b/tests/GraphQL/SortBlockMutationCreatorTest.php
index d474d3af..8c50499c 100644
--- a/tests/GraphQL/SortBlockMutationCreatorTest.php
+++ b/tests/GraphQL/SortBlockMutationCreatorTest.php
@@ -16,7 +16,7 @@ class SortBlockMutationCreatorTest extends SapphireTest
         TestElement::class,
     ];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
         if (!class_exists(Schema::class)) {
diff --git a/tests/Reports/ElementsInUseReportTest.php b/tests/Reports/ElementsInUseReportTest.php
index bb52a274..2f22432e 100644
--- a/tests/Reports/ElementsInUseReportTest.php
+++ b/tests/Reports/ElementsInUseReportTest.php
@@ -27,7 +27,7 @@ class ElementsInUseReportTest extends FunctionalTest
         TestPage::class,
     ];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
 
@@ -37,7 +37,7 @@ protected function setUp()
         }
     }
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         parent::tearDown();
         
@@ -53,18 +53,18 @@ public function testReportShowsElementsInUse()
 
         $result = (string) $this->get('admin/reports/show/DNADesign-Elemental-Reports-ElementsInUseReport')->getBody();
 
-        $this->assertContains('Content blocks in use', $result, 'Title is displayed');
+        $this->assertStringContainsString('Content blocks in use', $result, 'Title is displayed');
 
-        $this->assertContains(
+        $this->assertStringContainsString(
             'data-class="DNADesign\\Elemental\\Models\\ElementContent"',
             $result,
             'Report contains content elements (bundled with elemental)'
         );
 
-        $this->assertContains('HTML text block', $result, 'Content element "nice" type is shown');
+        $this->assertStringContainsString('HTML text block', $result, 'Content element "nice" type is shown');
 
-        $this->assertContains('My special content block', $result, 'Fixtured content element is shown');
-        $this->assertContains('Stubby Stub', $result, 'Fixtured stub element is shown');
+        $this->assertStringContainsString('My special content block', $result, 'Fixtured content element is shown');
+        $this->assertStringContainsString('Stubby Stub', $result, 'Fixtured stub element is shown');
     }
 
     public function testSourceRecords()
@@ -87,7 +87,7 @@ public function testElementsAssociatedToPagesHaveEditLink()
         $castros = $records->first();
         $this->assertNotNull($castros, 'Fixtured Castros page exists');
         $this->assertTrue($castros->hasField('EditLink'));
-        $this->assertContains(
+        $this->assertStringContainsString(
             (string) $this->idFromFixture(TestPage::class, 'castros_home'),
             $castros->EditLink,
             'Correct owner page ID is in edit link'
diff --git a/tests/Services/ElementTabProviderTest.php b/tests/Services/ElementTabProviderTest.php
index 05a53047..aa24d185 100644
--- a/tests/Services/ElementTabProviderTest.php
+++ b/tests/Services/ElementTabProviderTest.php
@@ -6,7 +6,7 @@
 
 class ElementTabProviderTest extends SapphireTest
 {
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
         $this->markTestIncomplete('Does not yet test anything, remains to be implemented');
diff --git a/tests/Tasks/MigrateContentToElementTest.php b/tests/Tasks/MigrateContentToElementTest.php
index 08d32a0a..9615430a 100644
--- a/tests/Tasks/MigrateContentToElementTest.php
+++ b/tests/Tasks/MigrateContentToElementTest.php
@@ -27,7 +27,7 @@ class MigrateContentToElementTest extends SapphireTest
         TestPage::class,
     ];
 
-    protected function setUp()
+    protected function setUp(): void
     {
         TestPage::create()->flushCache();
         parent::setUp();
@@ -46,7 +46,7 @@ public function testContentIsMigratedFromPagesToNewElements()
         $task->run(new HTTPRequest('GET', ''));
         $output = ob_get_clean();
 
-        $this->assertContains('Finished migrating 1 pages\' content', $output);
+        $this->assertStringContainsString('Finished migrating 1 pages\' content', $output);
 
         // Get the page that should've been updated and the content should be removed
         $page = $this->objFromFixture(TestPage::class, 'page3');
@@ -76,20 +76,20 @@ public function testContentIsNotClearedWhenConfigured()
         $task->run(new HTTPRequest('GET', ''));
         $output = ob_get_clean();
 
-        $this->assertContains('Finished migrating 1 pages\' content', $output);
+        $this->assertStringContainsString('Finished migrating 1 pages\' content', $output);
 
         $page = $this->objFromFixture(TestPage::class, 'page3');
-        $this->assertContains('This is page 3', $page->Content, 'Content is not removed from the page');
+        $this->assertStringContainsString('This is page 3', $page->Content, 'Content is not removed from the page');
 
         $element = $page->ElementalArea->Elements()->first();
-        $this->assertContains('This is page 3', $element->HTML, 'Content is still added to a new element');
+        $this->assertStringContainsString('This is page 3', $element->HTML, 'Content is still added to a new element');
 
         // Run the task again and assert the page is not picked up again
         ob_start();
         $task->run(new HTTPRequest('GET', ''));
         $output = ob_get_clean();
 
-        $this->assertContains('Finished migrating 0 pages\' content', $output);
+        $this->assertStringContainsString('Finished migrating 0 pages\' content', $output);
         $page = $this->objFromFixture(TestPage::class, 'page3');
         $this->assertCount(1, $page->ElementalArea->Elements());
     }
@@ -105,7 +105,7 @@ public function testTargetElementConfigurationIsRespected()
         $task->run(new HTTPRequest('GET', ''));
         $output = ob_get_clean();
 
-        $this->assertContains('Finished migrating 1 pages\' content', $output);
+        $this->assertStringContainsString('Finished migrating 1 pages\' content', $output);
 
         // Get the page that should've been updated and the content should be removed
         $element = $this->objFromFixture(TestPage::class, 'page3')->ElementalArea->Elements()->first();
@@ -129,7 +129,7 @@ public function testPublishingConfigurationIsRespected()
         $task->run(new HTTPRequest('GET', ''));
         $output = ob_get_clean();
 
-        $this->assertContains('Finished migrating 1 pages\' content', $output);
+        $this->assertStringContainsString('Finished migrating 1 pages\' content', $output);
 
         // Get the page that should've been updated and the content should be removed
         $page = $this->objFromFixture(TestPage::class, 'page3');
@@ -156,7 +156,7 @@ public function testPagesThatWereNotPublishedAreNotPublishedDuringThisTask()
         $task->run(new HTTPRequest('GET', ''));
         $output = ob_get_clean();
 
-        $this->assertContains('Finished migrating 1 pages\' content', $output);
+        $this->assertStringContainsString('Finished migrating 1 pages\' content', $output);
 
         // Get the page that should've been updated and the content should be removed
         /** @var TestPage&Versioned $page */
@@ -191,7 +191,7 @@ public function testIgnoredClassesContentIsNotCleared()
         $task->run(new HTTPRequest('GET', ''));
         $output = ob_get_clean();
 
-        $this->assertContains('Finished migrating 0 pages\' content', $output);
+        $this->assertStringContainsString('Finished migrating 0 pages\' content', $output);
 
         // Get the page and confirm its content has not been altered.
         $page = $this->objFromFixture(TestPage::class, 'page3');